Host-specificity and mimicry
The Vidua finches, including 10 species of indigobirds and 9 long-tailed whydahs (Sorenson et al. 2004), are of particular interest to ornithologists because of their high degree of host-specificity and their relatively benign effects on hosts as compared to other parasitic birds. Most species of indigobirds parasitize a single species of firefinch in the genus Lagonosticta (Payne 1996), although recent field studies (Payne et al. 1992, 2005; Payne & Payne 1994, 1995) have shown that indigobirds parasitize four additional estrildid finch species in four different genera (Table 1). The host-specificity of indigobirds is evidenced in two remarkable ways. First, nestling indigobirds are reared along with the host’s own young and young indigobirds mimic the mouth markings and begging behavior of their respective hosts (Nicolai 1964). Young firefinches and other estrildids have prominent and sometimes elaborate mouth markings, including patterns of black spots and/or lines on the palate and papillae of different sizes, shapes, and colors at the corners of the mouth (Payne 2005). These markings are important in securing parental care from the foster parents (Payne et al. 2001; Schuetz 2005a, 2005b). Most indigobirds show remarkably precise mimicry of the species-specific mouth patterns of their respective hosts (Figure 1).
Second, adult male indigobirds mimic the songs of their respective hosts (Payne 1973, 1976, 1982). Recent captive studies (Payne et al. 1998, 2000) have demonstrated that male village indigobirds (V. chalybeata) imprint on the songs of their foster parents as juveniles and mimic the songs of their host species as adults. Female indigobirds also imprint on songs of the host species and use these songs to choose both mates and the nests they parasitize.
Figure 1. Example of juvenile estrildid mouth markings and their mimicry in indigobirds. Photo credit: R. Payne.
Black-faced Firefinch (L. larvata)
Black-faced Firefinch Indigobird(V. larvaticola)
Table 1. Recognized indigobird species and their respective hosts.
Vidua chalybeata
“
V. camerunensis
“
“
“
V. codringtoni
V. funerea
V. larvaticola
V. maryae
V. nigeriae
V. purpurascens
V. raricola
V. wilsoni
Village Indigobird
“
Cameroon Indigobird
“
“
“
Peter’s Twinspot Indigobird
Dusky Indigobird
Black-faced Firefinch Indigobird
Jos Plateau Indigobird
Quail-finch Indigobird
Purple Indigobird
Goldbreast Indigobird
Bar-breasted Firefinch Indigobird
Lagonosticta senegala
L. nitidula
Clytospiza monteiri
Euschistospiza dybowskii
L. rara
L. rubricata
Hypargos niveoguttatus
L. rubricata
L. larvata
L. sanguinodorsalis
Ortygospiza atricollis
L. rhodopareia
Amandava subflava
L. rufopicta
Red-billed Firefinch
Brown Firefinch
Brown Twinspot
Dybowski’s Twinspot
Black-bellied Firefinch
African Firefinch
Peter’s Twinspot
African Firefinch
Black-faced Firefinch
Rock Firefinch
Quail-finch
Jameson’s Firefinch
Goldbreast
Bar-breasted Firefinch
Indigobird species
Host species
